REPORT DOCUMENTATION PAGE

Transcription

1 REPORT DOCUMENTATION PAGE Form Approved OMB No The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for information on Operations and Reports ( ), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) REPORT TYPE Final 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) Use of Controller Area Network (CAN) Data to Support Performance Testing 3. DATES COVERED (From - To) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHORS 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Automotive Instrumentation Division (TEDT-AT-ADI) US Army Aberdeen Test Center 400 Colleran Road, Building 436 Aberdeen Proving Ground, MD SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) Range Infrastructure Division (CSTE-TM) US Army Test and Evaluation Command 2202 Aberdeen Boulevard Aberdeen Proving Ground, MD DISTRIBUTION/AVAILABILITY STATEMENT 8. PERFORMING ORGANIZATION REPORT NUMBER TOP SPONSOR/MONITOR S ACRONYM(S) 11. SPONSOR/MONITOR S REPORT NUMBER(S) Same as item 8 Distribution Statement A. Approved for public release; distribution is unlimited. 13. SUPPLEMENTARY NOTES Defense Technical Information Center (DTIC), AD No.: 14. ABSTRACT This document provides guidance for using vehicle-based Controller Area Network (CAN) data during performance and endurance testing of military vehicles. Emphasis was given to use of standard Society of Automotive Engineers (SAE) J1939 CAN data to supplement other available data for vehicle testing, or be used in lieu of data that cannot be obtained otherwise. 15. SUBJECT TERMS Controller Area Network sensor electronic control unit diagnostic trouble codes digital interface 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT a. REPORT B. ABSTRACT C. THIS PAGE 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON Unclassified Unclassified Unclassified 19b. TELEPHONE NUMBER (include area code) SAR 20 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39-18

2 (This page is intentionally blank.)

3 US ARMY TEST AND EVALUATION COMMAND TEST OPERATIONS PROCEDURE * Test Operations Procedure DTIC AD No. USE OF CONTROLLER AREA NETWORK (CAN) DATA TO SUPPORT PERFORMANCE TESTING Page Paragraph 1. SCOPE Purpose Background INSTRUMENTATION General Instrumentation Setup Data Sample Rate EXAMPLES OF SENSOR DATA USAGE Vehicle Speed Engine Speed Vehicle Odometer Fuel Consumption Transmission Feedback Vehicle Stability Systems Tire Status DIAGNOSTIC DATA USAGE DATA REQUIRED PRESENTATION OF DATA... 9 APPENDIX A. GLOSSARY... A-1 B. ABBREVIATIONS... B-1 C. REFERENCES... C-1 D. APPROVAL AUTHORITY... D-1 Approved for public release; distribution unlimited.

4 1. SCOPE. This Test Operations Procedure (TOP) provides guidance for using vehicle-based Controller Area Network (CAN) data during performance and endurance testing of military vehicles. 1.1 Purpose. a. Vehicle CAN data may be used to supplement available test data from traditionally applied (National Institute of Standards and Technology (NIST)-traceable and calibrated) transducers during testing, provided CAN data accuracy is verified, the verification is documented in associated test reports, and use of the CAN data source is stated in the test report identifying the corresponding data channels. Documentation should include sample frequency, full-scale range, and resolution of the CAN data channel. A CAN data channel may also be used in lieu of a traditionally applied transducer channel when the applied transducer fails or becomes inoperable during a test and retesting is not an option. b. There may be cases of use when the accuracy and frequency of specific CAN data channels cannot be independently verified, such as when vehicle-based controllers provide error messages regarding system functions (e.g., electronic stability control system fault). The information provided by the vehicle-based data channels may be highly valuable information for testing and analysis purposes, particularly when controller diagnostic information is available for analyzing system performance and limitations. In such cases, use of the data are acceptable provided the data source is stated in the test report. c. The scope of this TOP is limited to the CAN application layer. Network, data link, and physical layer implementations are not addressed. 1.2 Background. a. A CAN is a standardized digital interface that allows the communication of information in a vehicle between sensors, electronic control units, and computers. A number of sources provide details on the implementation and common message formats, including International Organization for Standardization (ISO) (Parts 1through 6) **1 and the Society of Automotive Engineers (SAE) J1939 2,3,4. The specification CAN 2.0 was published by Bosch in 1991 and was in use when this document was authored. CAN is a message-based protocol with two different formats. The first format uses an 11-bit message identifier and is referred to as CAN 2.0A. The second format uses an extended 29-bit message identifier and is referred to as CAN 2.0B. ** Superscript numbers correspond to Appendix C, References. 2

5 b. The SAE J1939 protocol is a variant of CAN 2.0B and is the SAE recommended practice for communication and diagnostics of vehicle systems in the heavy-truck, bus, and offhighway vehicle industry. The J1939 protocol is present in many wheeled military vehicles and is also found on engines used in military generators. The SAE J1939 standards collection (J1939 and J1939 supplemental documents) lays out the format of standard data messages needed to monitor vehicle systems. The J1939 standards also provide the framework for receiving realtime diagnostic error messages and reading historical fault codes from vehicle systems. c. Besides standard J1939 and CAN messaging, most military vehicle systems also utilize proprietary CAN messages. Typically an interface control document (ICD), defining the proprietary CAN messages, is available from the program management office. The ICD should define the available proprietary CAN messaging and diagnostic messages (DM). 2. INSTRUMENTATION. 2.1 General. Test instrumentation with traditional user-installed sensors will continue to be used in physical test roles to gather calibration traceable data on system performance. The instrumentation system should be capable of also recording CAN data and diagnostic messaging information. For typical operation, the data acquisition system should remain in a passive state to avoid interaction with any of the controllers on the CAN data bus. If user-installed sensors and CAN data are to be recorded, then the data acquisition system should be capable of simultaneously recording both data types. 2.2 Instrumentation Setup. The setup of a data acquisition system for CAN bus recording typically starts with defining the desired messages and signals to be recorded. The available signals can be identified by three methods: a database CAN (DBC) file, a vendor-provided ICD, or a scan and analysis of the vehicle data bus. The DBC file type is a common format compatible with most data acquisition and CAN programs. The DBC file contains the description of the connected controllers, messages and signals for the CAN network. If a DBC file is not available, it is good practice to develop a DBC file for each CAN network that will be recorded during testing. A DBC file can be built from the vendor provided ICD and then used to configure the appropriate signal channels on the data acquisition system. If no documentation is available, a scan (using a commercial CAN analyzer) of the CAN data bus provides an overview of available messages and signals. The CAN data bus scan can then be compared to the SAE J1939 and ISO standards to determine the available signals. The number of signals available for monitoring will vary depending upon the age and electrical complexity of the system under test. 3

6 2.3 Data Sample Rate. The data sample rate for the CAN bus varies depending upon the message. CAN is known as an asynchronous data stream, meaning the CAN bus messages and signals arrive at different times and are not synchronized with each other. The samples rates of the data channels are not necessarily consistent and therefore should not be used for any data that requires a frequency domain analysis. The sample rate of the CAN data should be verified before test execution to verify that the CAN data will provide the necessary information to analyze system performance. If data with synchronized time steps are required, then user-installed instrumentation should be added to meet test data requirements. 3. EXAMPLES OF SENSOR DATA USAGE. The examples below highlight some common CAN data that have been recorded and utilized for vehicle analysis. This is not an exhaustive list. 3.1 Vehicle Speed. a. The SAE J1939 digital annex 5 lists a data channel in the cruise control/vehicle speed (CCVS) message as an estimate for wheel-based vehicle speed. The wheel-based vehicle speed estimate typically is provided from the engine controller, brake system controller, or both. The wheel-based speed can be verified by comparison to global positioning system (GPS) sensor data, or another calibrated speed sensor installed on the vehicle. The acceptable error for vehicle speed measurement for use during vehicle endurance testing is specified in the instrumentation section of TOP The acceptable error for data used as a substitute for vehicle performance testing is typically specified in instrumentation section of the appropriate performance TOP. b. The wheel-based vehicle speed channel is a direct measure of the axle rotation speed. Therefore, in conditions where the tire loses traction with the ground, the reported vehicle speed will not be an accurate indication of vehicle speed. A typical case for using the J1939 reported vehicle speed is when foliage or an obstructed view of the sky causes loss of GPS signal. The wheel-based data can be verified from data collected when a GPS signal was available. An example of this test usage case is presented in Figure Engine Speed. The SAE J1939 digital annex lists a channel in the electronic engine controller 1 (EEC1) message as an estimate for engine rotational speed. The engine speed is provided by the vehicle s engine controller. The engine speed can be verified at idle with the use of a stroboscope, or pulse emitting sensor integrated into the data acquisition system. The acceptable error for engine speed data used in a system performance analysis is typically provided in the instrumentation section of the applicable TOP. 4

7 Figure 1. Example scenario for J1939 speed usage. 3.3 Vehicle Odometer. a. The SAE J1939 digital annex lists several channels that provide an estimate of the distance traveled by a vehicle. The messages are high resolution vehicle distance (VDHR) and vehicle distance (VD). The vehicle mileage messages are often redundantly broadcast on the data bus by multiple controllers. Therefore, the specific distance message should be verified and compared to the actual odometer value shown on the vehicle s gauge cluster unit. b. The vehicle odometer is typically used for tracking mileage throughout vehicle testing. The odometer reading is used in analysis for distance-based system reliability estimates. Therefore, it is essential to validate that the accuracy of the odometer reading, so that test results between different vehicles systems have a meaningful correlation. The odometer should be verified at a vehicle speed of 70 kilometers per hour (km/hr) as specified in TOP Fuel Consumption. a. The SAE J1939 digital annex lists several common channels for monitoring vehicle fuel usage. The message fuel economy liquid (LFE) provides a real-time estimate of the vehicle fuel rate and fuel economy. The message fuel consumption liquid (LFC) is a request-based message that provides an estimate of total vehicle fuel consumption. A request-based message requires the instrumentation to send a request to the engine controller to supply the desired message. Another request based message, idle operation (IO), can potentially provide the total idle fuel consumption. 5

8 b. Fuel consumption CAN data accuracy should be validated prior to, or during fuel consumption testing using an external fuel flow measurement system (described in TOP A 7 ) as a reference. The CAN fuel rate channel should be integrated and compared to the total consumption measured with the fuel measurement system. Scalar correction factors can be determined and applied to the CAN fuel rate LFE message data by averaging or least-squares fitting multiple test runs at different speeds and terrain types. A comparative example of data from an external fuel measurement system (fuel meter), uncorrected J1939 fuel data, and corrected J1939 fuel data are presented in Figure 2. Figure 2. Comparison of fuel rate data. 3.5 Transmission Feedback. The SAE J1939 digital annex lists messages that monitor transmission operating states. For many performance tests it is important to know the current transmission gear setting, as well as torque converter state. The message electronic transmission controller 2 (ETC2) provides data channels for monitoring the current and selected transmission gears. The messages electronic transmission controller 8 (ETC8) and electronic transmission controller (ETC1) provide information about the transmission torque converter status. The operating state of the torque converter is critical information for powertrain testing. If available on the CAN, this information should be captured for all powertrain related performance testing. 6

9 3.6 Vehicle Stability Systems. a. The SAE J1939 digital annex provides messages that monitor the status and functionality of vehicle anti-lock braking (ABS), anti-slip regulation/traction (ASR), and electronic stability control systems (ESC). The ESC systems are referred to as vehicle dynamic control (VDC) systems in the J1939 documents. The proper functionality of vehicle control systems is necessary for conducting braking, acceleration, and steering and handling performance testing. The message electronic brake controller 1 (EBC1) provides the status of ABS and traction control systems. The message also provides an indication if the brake controller is intervening with vehicle operation. The messages vehicle dynamic stability control 1 (VDC1) and VDC2 provide status information for the vehicle s dynamic stability control operation. The VDC2 data channel provides the active feedback the ESC system sensors. Vehicle steering wheel angle, yaw rate, lateral acceleration, and longitudinal acceleration are also available signals associated with vehicle stability control. b. The system status signals can be verified prior to testing by disabling the systems and monitoring the state of the fully-operational status channels. The vehicles often provide a switch on the dash to disable the stability or traction control systems. The dynamic signals from the VDC2 message can be verified with the installation of a calibration-traceable inertial system mounted inside the vehicle cab. The inertial system should be located as close as possible to the sensor used for the vehicle stability control system. The data from the two inertial systems are compared for validation of the vehicle s signal data. A comparative example of CAN data used during steering and handling testing is shown in Figure 3. The VDC operational channel indicates that the stability control system was intermittently switching off by the vehicle controller during testing. In one case, the system switched off during a test run. Using the CAN data the test engineer was able to determine that the system was not functioning properly, and which test runs were invalid for analysis purposes. 7

10 Figure 3. Example of diagnostic trouble codes (DTC) and stability system data. 3.7 Tire Status. Most military vehicles currently include a central tire inflation system (CTIS). The CTIS is controlled by inputs from the driver based on the vehicle weight and expected terrain type. The CTIS usually broadcasts vehicle tire pressure, driver selected settings, and any system faults. The SAE J1939 digital annex lists the Tire Condition (TIRE) message for monitoring tire pressure and CTIS conditions. Tire pressure is an important data channel to monitor during steering and handling and braking tests. The accuracy of the CAN tire pressure data may be verified by comparing to a calibrated tire pressure gauge. The accuracy should be checked at two different tire pressure settings. The measurements should fall within the tolerances specified in TOP A DIAGNOSTIC DATA USAGE. a. The J1939 protocol provides standardized reporting of DTCs. The DTC s are integer fault codes that describe the failure type and count of the failure occurrences. DTC s are available in several request-based messages, however this TOP focuses only on the active diagnostic trouble codes message (DM1). The DM1 message provides a method to indicate active faults recognized by the system controllers. The active faults can often be associated with anomalies seen during vehicle performance testing. Not all vehicle diagnostic trouble codes are actively broadcasted. Only DTC s selected by the specific subsystem vendor are actively broadcasted. The DTC provides the suspect parameter number (SPN), failure mode identifier 8

11 (FMI), and occurrence count (OC). The SPN and FMI can then be mapped to either a standard contextual definition or a proprietary definition provided in a manufacturer s ICD. b. An example of DTC used during steering and handling testing is presented in Figure 3. An intermittent fault was present during a steering and handling test. The fault message coincided directly with the disabling of the stability control system. The CAN data provided insight into an intermittent fault that would have otherwise been difficult to recognize and diagnose. 5. DATA REQUIRED. The CAN data required to support vehicle performance testing is dependent upon the subject of the performance sub-test. All data to be collected should be documented in the test plan, to include the method and instrumentation used, and should be agreed upon by the U.S. Army Test and Evaluation Command (ATEC) System Team (AST). Sections 3 and 4 of this TOP provide examples of data that can be collected from the vehicle CAN. 6. PRESENTATION OF DATA. The format for data presentation should be determined by the AST. Examples of how data can be presented are provided in Figures 1 through 3 of this TOP. 9

12 (This page is intentionally blank.)

13 16 july 2015 APPENDIX A. GLOSSARY Term Failure Mode Identifier (FMI) Suspect Parameter Number Definition The FMI defines the type of failure detected in the subsystem identified by an SPN (SAE J ). This 19-bit number is used to identify the item for which diagnostics are being reported (SAE J ). Diagnostic Trouble Code (DTC) A 4 byte value that identifies the kind or trouble, the associated failure mode, and its occurrence count (SAE J ). A-1

14 (This page is intentionally blank.) A-2

15 APPENDIX B. ABBREVIATIONS. ABS ASR AST ATEC CAN CCVS CTIS DBC DM DTC EEC ESC ETC FMI GPS ICD IO ISO km/hr LFC LFE NIST OC SAE SPN TIRE TOP VD VDC VDHR. anti-lock braking system anti-spin regulation U.S. Army Test and Evaluation Command (ATEC) System Team U.S. Army Test and Evaluation Command Controller Area Network cruise control/vehicle speed central tire inflation system Controller Area Network (CAN) database file diagnostic message diagnostic trouble code electronic engine controller electronic stability control electronic transmission control failure mode identifier global positioning system interface control document idle operation International Organization of Standardization kilometers per hour Fuel consumption liquid fuel economy liquid National Institute of Standards and Technology occurrence count Society of Automotive Engineers suspect parameter number tire condition Test Operations Procedure vehicle distance vehicle dynamic control high resolution vehicle distance B-1

16 (This page is intentionally blank.) -2

17 APPENDIX C. REFERENCES. 1. ISO 11898: Road Vehicles - Controller area network (CAN) - Part 1 through Part 6: ISO : Data link layer and physical signaling: ISO : High-speed medium access unit: ISO : Low-speed, fault-tolerant, medium-dependent interface: ISO : Time-triggered communication: ISO : High-speed medium access unit with low-power mode: ISO : High-speed medium access unit with selective wake-up functionality: SAE J1939, Serial Control and Communications Heavy Duty Vehicle Network - Top Level Document, 14 August SAE J , Vehicle Application Layer, 28 April SAE J , Application Layer - Diagnostics, 24 July SAE J Digital Annex (technical data in spreadsheet form), 20 February TOP , Inspection and Preliminary Operation of Vehicles, 4 February TOP A, Vehicle Fuel Consumption, 10 May TOP A, Tires, DRAFT, 31 March C-1

18 (This page is intentionally blank.) -2

19 APPENDIX D. APPROVAL AUTHORITY. CSTE-TM MEMORANDUM FOR Commanders, All Test Centers Technical Directors, All Test Centers Directors, U.S. Army Evaluation Center Commander, U.S. Army Operational Test Command SUBJECT: Test Operations Procedure (TOP) , Use of Controller Area Network (CAN) Data to Support Performance T estjing, Approved for Publication 1. TOP , Use of Controller Area Network (CAN) Data to Support Performance Testing, has been rev.iewed by the U.S. Army Test and Evaluation Command (ATEC) Test Centers, the U.S. Army Operational Test Command, and the U.S. Army Evaluation Center. All comments received during the formal coordination period have been adjudicated by the preparing agency. The scope of the document is as follows: This TOP provides guidance for using vehicle-based CAN data during performance and endurance testing of military vehicles. Emphasis was given to the use of standard Society of Automotive Engineers (SAE) J1939 CAN data to supplement other available data for vehicle testing, or be used in lieu of data tlnat cannot be obtained otherwise. 2. This document is approved for publication and has been posted to the Reference Ubrary of the ATEC Vision Digital Ubrary System (VDLS). The VDLS website can be accessed at 3. Comments, suggestions, or questions on this document should be addressed to U.S. Army Test and Evaluation Command (CSTE-TM), 2202 Aberdeen Boulevard-Third Floor, Aberdeen Proving Ground, MD ; or ed to usarmy.apg.atec.mbx.atecstandards@mail.mil. FOR.. FONTAINERAvt.IO ::"".:.::::-'..!.--:':. NO.G_ nO :::::: - - ~~,,... RAYMOND G. FONTAINE Associate Director, Test Management Directorate (G9) MICHAEL J. ZWIEBEL Director, Test Management Directorate (G91) D-1

20 (This page is intentionally blank.) D-2

21 Forward comments, recommended changes, or any pertinent data which may be of use in improving this publication to the following address: Range Infrastructure Division (CSTE-TM), US Army Test and Evaluation Command, 2202 Aberdeen Boulevard, Aberdeen Proving Ground, Maryland Technical information may be obtained from the preparing activity: Automotive Instrumentation Division (TEDT-AT-AD-I), U.S. Army Aberdeen Test Center, 400 Colleran Road, Aberdeen Proving Ground, Maryland Additional copies can be requested through the following website: or through the Defense Technical Information Center, 8725 John J. Kingman Rd., STE 0944, Fort Belvoir, VA This document is identified by the accession number (AD No.) printed on the first page.